When we recommend an overlay
- Glue-down LVT or vinyl over boards or chipboard that aren't smooth or stable enough for direct adhesion.
- Older, uneven floorboards with gaps or minor undulation that would telegraph through a thin finish.
- Adding stiffness over suspended timber before a more rigid floor covering.
How we check the existing floor first
Before any ply goes down we check the base floor is dry, structurally sound and free of active movement. Screwing plywood over damp or rotten boards doesn't fix anything — it just adds a layer that has to be pulled back up later, so we're upfront if we think the base needs attention first rather than an overlay.
What goes wrong when an overlay is skipped where needed
Adhesive-based floors like glue-down LVT can fail to bond properly to an uneven or porous chipboard surface, leading to lifting seams and hollow-sounding patches within a relatively short time. Thinner finishes will also show every gap and unevenness in the boards beneath, which is a common complaint we're called out to after DIY jobs.
Which finishes typically need it
Glue-down LVT and sheet vinyl are the main candidates, along with some tile-look rigid products. Floated floors like laminate and click LVT are generally more forgiving of minor unevenness because the underlay takes up some of the difference.
Fife reality: older Dunfermline and Kirkcaldy terraces
In older terraced streets around Dunfermline and Kirkcaldy, original floorboards are often narrower with more joints than modern timber, and decades of sanding have sometimes left them slightly cupped. An overlay here is often less about strength and more about giving a smooth, consistent surface for adhesive-based finishes.